Multiple barrel mine anchor-line cutter



Feb. 13, 1962 R. TEMPLE ETAL MULTIPLE BARREL MINE ANCHOR-LINE CUTTER 2Sheets-Sheet 1 Filed Jan. 14. 1959 l ENTORS Efi/VEST TE/YPL 5 Theirflttohhe/s Feb. 13, 1962 R. TEMPLE ETAL 3,020,871

MULTIPLE BARREL MINE ANCHOR-LINE CUTTER Filed Jan. 14, 1959 2Sheets-Sheet 2 sweep line.

Sfifihfi'll Patented Feb. 13, 1962 This invention relates to cuttingdevices, by which the lines that anchor buoyant explosive mines underwater can be severed, and more particularly to such cutters that areexplosively actuated.

It is common practice to pull explosively actuated mine anchor-linecutters through the water by means of sweep lines attached to ships. Inan attempt to reduce the number of individual cutters, several of themhave been provided with the same stabilizing fin. Even with such anarrangement, the cutters create a considerable drag on It has recentlybeen proposed to pull the sweep lines. the sweep lines through the waterby helicopters flying just above the surface, but the drag offered byknown cutters is still too great to make that feasible.

It is among the objects of this invention to provide a mine anchor-linecutter, which carries a plurality of cutting elements that operate insuccession, which does not create turbulence in the water, which doesnot attempt to dive or rise, which is considerably lighter than theaggregate number of single barrel cutters required for carrying a likenumber of cutting elements, in which the stabilizing fin can be quicklyattached and detached, and in which the firing mechanism is sealed fromthe surrounding water both before and after the cutter has beenoperated.

The preferred embodiment of the invention is illustrated in theaccompanying drawings, in which I FIG. 1 is a plan view of our cuttermounted on a sweep FIG. 2 is a front view thereof;

FIG. 3 is a view of the cutter showing the front end of the frame;

FIG. 4 is a viewof the opposite end of the frame;

FIGS. 5 and 6 are enlarged fragmentary horizontal sections taken on thelines V-V and VIVI, respectively, of FIG. 2;

FIGS. 7 and 8 are fragmentary vertical sections taken on the linesVII-NH and VIIIVIII, respectively, of FIG. 5; and

FIG. 9 is a side view of one of the cartridges used in the cutter.

Referring to FIG. 1 of the drawings, a number of our mine anchor-linecutters are mounted on a sweep line 1 and towed through the water in thedirection of the arrow by a mine sweeper or a helicopter. The sweep lineis held at the desired angle and depth by means which form no part ofthis invention. Each cutter has two major parts; an elongated tool frame2 and a tapered fin 3 that keeps the frame more or less horizontal andheaded forward. To permit the cutter to be mounted on the sweep line,the frame isprovided with a central longitudinal slot 4 that opensrearwardly, as shown in FIGS. 3 to 8. The slot is just wide enough toaccommodate the sweep line, which is held in it by the front end of thefin.

The fin includes a thin flat vane 6, the narrow front end of which isrigidly mounted in a metal bar 7. The bar has at one end a tongue 8 thatextends into the front end portion of the frame slot and nearly engagesthe Opposite sides of the tongue are provided with ribs 9 that extendlengthwise of the frame a short distance and that are slidably mountedin grooves 10 formed in the opposite side walls of the slot. The ribsare inserted in the grooves by mov'mg the bar backwardalong the frame.The opposite or rear end of the bar is provided with an integral lug 11of reduced thickness, which slides into a notch 12 in a tail-piece 13fastened to the rear end of the frame by a central screw 14. The lug isheld in the notch by a spring-pressed pin 15 mounted in one side of thetail-piece and projecting into a depression 16 in the side of the lug.The lug also is provided with a notch 17a extending from the depressionto the rear end of the bar. Beside the open end of this notch the lughas inclined surfaces 17 that engage the pin 15 and depress it while thebar moves back, until the pin can snap out into depression 16. The baralso has a small tongue 18 that projects into the rear end of frame slot4 and nearly engages the sweep line. To enclose the exposed rear edgesof bar 7 and help hold the vane in place, curved members 19 fit over theopposite sides of the 'bar and engage the adjacent areas of the vane.The outer surfaces of these members curve forward from the vane to theupper and lower sides of the frame and form smooth surfaces for water toflow across. It will be seen that it is an easy matter to disconnect thecutter from the sweep line, by merely pushing the spring-pressed pin 15back out of lug depression 16 by means of an instrument (not shown)inserted in a passage 20 in the opposite side of tail-piece 13. The headof the fin can then he slid toward the front end of the frame slot aslug notch 17a slides off the pin-depressing instrument. The tool framethen can be lifted off the sweep line.

Another feature of this invention is that the tool frame is providedwith at least two cutting elements, most suitably in the form ofcylindrical chisels. Preferably, there are two chisels 21 and 22slidably mounted in parallel barrels 23 formed in the front side of theframe 2 at opposite sides of slot 4, about mid-way between the ends ofthe frame. As shown in FIGS. 5 and 6, the front of the frame at its rearend is cut away and the adjacent ends of the barrels are open. That is,the barrels open into mine anchor-line receiving recesses that areformed between the front of the frame and a couple of anvils 24 and 25staggered lengthwise of the frame. The anvils have rear ends that fit inparallel slots 26 and 27 (FIGS. 2 and 4) in the rear end of the frameand tail-piece 13. Slot 26 extends lengthwise of the frame farther thanthe other so that anvil 24 will be located closer to chisel 21 than theother anvil is located relative to chisel 22. The anvils are held in theslots by shear screws 28. Each anvil extends forward perpendicularly tothe frame and then laterally a short distance toward the opposite end ofthe frame and then forward again at an oblique angle. When the frameengages the first mine anchor-line 29 (FIG. 1) the frame will slideacross the line, which will be directed by the front end of the forwardanvil 24 into the recess that the anvil and frame form in line withchisel 21.

To drive the chisels out of the barrels, an explosive cartridge 31 isdisposed in each barrel. As shown in FIG. 5, each cartridge has a baseportion with a thick side wall located directly behind the chisel andsubstantially filling the inner end of the barrel. The rest of thecartridge has a thin side wall that extends forward into an axial bore32 in the inner or rear end of the chisel. This telescoping of chiseland cartridge permits the length and weight of the frame to be reduced.When such a cartridge is fired, its side wall is ruptured where the thinwall joins its heavy wall. This allows the expanding gases to engage therear end of the chisel around its central bore and thereby the gases actupon a greater area of the chisel than just the inner end of the bore.Of course, the thin wall portion of the cartridge leaves the cutter withthe chisel. The force of the explosion also expands the base portion ofthe cartridge, which feinains in thefratne after firing, so thatthebaseportion will not be thrown out of the barrel when the secondcartridge is fired, which would allow water and mud and the like to foulthe first firing pin,

The base portion of each cartridge is threaded so that a threaded rod(not shown) can be inserted in the barrel and screwed into the cartridgebase in order to pull it out of the barrel to permit the tool to bereloaded. The base portion of each cartridge also is provided withaperipheral groove, in which is mounted asealing ring 33 thatcom-pressed against the side of the barrel to prevent water from seepingpast the cartridge. 'It is likewise preferred to mount an additionalsealing ring 34 in a groove around the chisel to keep water from evenreaching the cartridge before it is fired.

' In order to tire the cartridges, a firing pin 36 is slidably mountedin a small hole in the frame directly behind each cartridge. Each pinissupported by a cylindrical slide 37, preferably integral with it, thatis movable-back and forth in a bore 38 in the frame; The pin is urgedaway from the cartridge by a coil spring 39 compressed between ashoulder on the slide and the front end of the bore. The

rear end of the bore is closed by a plug 40 that is encircled by anO-ring 41 which seals that end of the bore. Extending out of one side ofthe rear end of the bore, preferably atright angles to it, is a passage42, which has an outer end portion that extends back through the frametoward the anvils. The outer end of the passage opens into a small slot43 in the frame, which is open to the surrounding weer. r slidablymounted in the portion of passage 42 that is perpendicular to bore 38,is a piston 45 provided with a circumferential groove in which a sealingring 46 is compressed to prevent water from passing the piston andgetting into the slide bore. The adjoining ends of the piston andfiringpin slide engage each other alongsurfaces in clined to their axes,so that if the piston is pushed farther into the bore, it will pushthefiring pin toward the cartridge. The meeting ends of the piston andslide are held together by a hook and pin. Preferably the pin 47 ismounted across a slot 48 (FIG; 7) extending diagonally across thepiston, and the hook 49 projects from the inner 'end of the slide intothe slot and part way around the pin. .If the tool is dropped, this pinand hook connection will prevent the jar from accidentally forcing thefiring pin against the cartridge. The connection also prevents therecoil due to firing of one cartridge from causing the other firing pinslide to move toward the other cartridge and fire it.

When it is time to fire a cartridge, the water in a passage 4-2 issuddenly put under sufficient pressure to drive the piston thereinforward against the adjoining slide 37, which is thereby forced towardthe cartridge. The water pressure is created by a plunger Stl slidablymounted in a recess in the back side of the frame. The exposed side ofeach recess can be closed by a cover plate 51. Each plunger normally isheld in a retracted position, with its front end behind the water inletslot 43, by means of a headed trigger pin 52 extending through a hole inthe frame as shown in FIG. 5. The inner end of the pin projects into ahole 53 in the plunger near its rear end, and the outer portion of thepin extends across the cutting recess and through the adjoining anvil.When the inner end of the trigger pin is withdrawn from the plunger, thelatter is shot forward by a coil spring 54 compressed between a shoulder55 on the plunger and a washer 56 slidably mounted on the plunger andbearing against the frame. A shear pin 57 in the chisel compels theexplosion to build up considerable pressure before that pin is shearedoff and the chisel 21 shot out of the barrel with great force. In fact,the force is great enough to cut the anchor-line and break the shear pin28 by which the anvil 24 is held in place, so that the anvil willseparate from .the frame and not catch. on the next mine anchor-line.

The latter is thus free to be caught by anvil 25 and to fire the othercartridge so that chisel 22 will cut the line. The rear ends of plungers50 are threaded so that they can be gripped by a threaded socket member(not shown) and pulled back to cock the tool after new anvils andtrigger pins have been installed.

It will be seen that a single, light Weight frame carries two chisels,so that the cutterwill create considerably less drag on a sweep linethan would two ordinary single barrel cutters. Another big advantage isthat the sealing rings keep all water awayfrom the firing mechanism.That is highly desirable because water would interfere with the actionat the firing pins. Also where water can enter, silt, sand and mud canenter likewise, and that means that the firing mechanism would have tobe dismantled and cleaned after every use of the cutter. Our inventionmakessuch cleaning unnecessary.

The stabilizing fin can be quickly snapped into place in v cuttertherefore can be pulled through the water at a speed of between twentyand thirty knots by a helicopter.

The location of thesweep line in the tool frame. near its front side,and the tapered front end of the frames assures that a mine anchor-linewill pass smoothly from the sweep line along the frame to the cuttingrecess without jumping over the anvils.

According to the provisions of thepatent statutes, we have explainedtheprinciple of our invention and have illustrated and described what wenow consider to represent its best embodiment. However, we desire tohave it understood that, within the scope of theappended claims, theinvention may be practiced otherwisethan as specifically illustrated anddescribed.

We claim:

1. A mine anchor-line cutter comprising a frame, a longitudinallymovable cutting element in the frame, means connected to the frameadjacent the cutting end of said element for receiving an anchor-line inposition for cutting, a cartridge in the frame at the opposite end ofsaid element, a sealing ring encircling the cartridge to keep water frompassing it, the frame being provided behind the cartridge with a bore, afiring pin in the bore, a slide in the bore behind the pin for moving itforward, the frame being provided with a passage open at one end andhaving its opposite end opening into the rear end of said bore at anangle thereto, a piston in said passage engaging the rear end of saidslide, the engaging ends of said piston and slide being inclined to theaxes of the piston and slide, a sealing ring encircling the piston insealing engagement therewith and with the wall of said passage, andspring-actuated means carried by the frame for forcing water into saidopen end of the passage to cause the piston to move the slide forward.

2. A mine anchor-line cutter comprising a frame, a pair of laterallyspaced parallel cutting elements slidably mounted in the frame, meansconnected to the frame adjacent the cutting ends of said elements forreceiving anchor-lines in position for cutting, the frame being formedto support explosive means adjacent the opposite end of said elementsfor driving them toward said linereceiving means, said frame beingprovided with a central longitudinal slot for receiving a sweep line,said slot opening to the rear of the frame, and a stabilizing finattached to the frame and having its front end closing the open side ofthe slot to retain a sweep line therein.

3. A mine anchor-line cutter comprising a frame, a pair of laterallyspaced parallel cutting elements slidably mounted in the frame, meansconnected to the frame adjacent the cutting ends of said elements forreceiving anchor-lines in position for cutting, the frame being formedto support explosive means adjacent the opposite end of said elementsfor driving them toward said linereceiving means, said frame beingprovided with a central longitudinal slot for receiving a sweep line,said slot opening to the rear of the frame, and a stabilizing fin havingits front end mounted in said slot and formed to hold a sweep lineagainst the front Wall of the slot.

4. A mine anchor-line cutter comprising a frame, a pair of laterallyspaced parallel cutting elements slidably mounted in the frame, meansconnected to the frame adjacent the cutting ends of said elements forreceiving anchor-lines in position for cutting, the frame being formedto support explosive means adjacent the opposite end of said elementsfor driving them toward said linereceiving means, said frame beingprovided with a central longitudinal slot for receiving a sweep line,said slot opening to the rear of the frame, a stabilizing fin having itsfront end extending into said slot, the slot and fin being provided atone end of the frame with interengaging ribs and grooves extendinglengthwise of the frame, and means at the opposite end of the framedetachably connecting the fin and frame together.

5. A mine anchor-line cutter comprising a frame, a pair of laterallyspaced parallel cutting elements slidably mounted in the frame, an anvilspaced from the cutting end of each cutting element and forming with theframe a recess for receiving a mine anchor-line, a shear pin connectingeach anvil to the frame, the anvils ,being spaced different distancesfrom the adjacent cutting elements, the frame being formed adjacent theopposite end of said elements with explosive means receiving chambers,and means in said recesses engageable by mine anchor-lines in successionfor firing explosive means in said chambers in succession to drive thecutting elements against the anvils with suificient force to shear saidpins.

6. A mine anchor-line cutter comprising a longitudinally movable cuttingelement, means adjacent the cutting end of said element for receiving ananchor-line in position for cutting, means adjacent the opposite end ofsaid element to receive an explosive charge, a firing pin for explodingthe charge to actuate the cutting element, a slide behind the pin formoving it ahead, a piston disposed at an angle to the rear end of theslide, the slide and piston having inclined engaging end surfaces, theadjoining ends of said slide and piston being provided with aninterengaging hook and cross pin for holding them together, andspring-actuated means for forcing 6 water against the piston to cause itto push said slide ahead.

7. A mine anchor-line cutter comprising a frame, a pair of laterallyspaced parallel cutting elements slidably mounted in the frame, meansconnected to the frame adjacent the cutting ends of said elements forreceiving anchor-lines in position for cutting, the frame being formedto support explosive means adjacent the opposite end of said elementsfor driving them toward said line-receiving means, said frame beingprovided with a central longitudinal slot for receiving a sweep line,said slot opening to the rear of the frame, a stabilizing fin having itsfront end extending into said slot, the slot and fin being provided atone end of the frame with interengaging ribs and grooves extendinglengthwise of the frame, the fin at the opposite end of the frame beingprovided with a lateral recess, and a spring pressed pin mounted in theframe beside said recess and projecting into it to detachably lock thefin and frame together.

8. A mine anchor-line cutter comprising a frame, a pair of laterallyspaced parallel cutting elements slidably mounted in the frame, an anvilspaced from the cutting end of each cutting element and forming With theframe a recess for receiving a mine anchor-line, a shear pin connectingeach anvil to the frame, one of the anvils being located closer than theother to the adjacent end of said frame, the frame being formed adjacentthe ends of said elements opposite their cutting ends with explosivemeans receiving chambers, and means in said recesses engageable byanchor-lines in succession for firing explosive means in said chambersin succession to drive the cutting elements against the anvils withsufficient force to shear said pins.

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